Michelle Gray tested positive for THC, but she wasn’t impaired.

A Halifax woman who uses cannabis to manage her multiple sclerosis had her driver’s licence revoked and her car impounded during a roadblock in early January, even though cops determined she was not impaired.

Michelle Gray, 38, is a medical cannabis patient. She told VICE she uses either dried cannabis or a combination THC/CBD oil to deal with a number of issues relating to her MS—including inflammation of her optic nerves—as well as insomnia, anxiety, and post-traumatic stress disorder stemming from an abusive former relationship.

“I have a very high tolerance for it,” she said, noting she first started using weed as a teenager.

Gray, who works in security, says she consumed about “half of a tiny joint” around 4 PM on January 4. Later that evening, she took her son out to dinner to celebrate his 19th birthday. At dinner, she said she had one drink.

On their way home, at around 10:45 PM, they were pulled over at a roadblock in Lower Sackville.

Gray said she told the RCMP officer she’d had one drink. He asked her to take a breathalyzer, which she agreed to and passed, and also asked if she had weed in the car because he said he could smell it. Gray told him she did have cannabis in the car and he advised her to put it in her trunk, as per the province’s rules.

Gray said she also agreed to take a roadside oral fluid test—one of the new testing methods some police forces are using to detect high drivers. It came back as positive—meaning she was over the cut off—but Gray wasn’t told the specific THC levels in her system. She was placed under arrest and her car was impounded. Her son had to get a ride home from a relative.

Gray was given the option of having blood work done or going to a Halifax police station and doing a more extensive sobriety test with a drug recognition expert (DRE)—a cop specially trained to detect drug impairment.

“I went into this concrete room and it has a tape line on the floor and things like that,” Gray explained. A DRE evaluation includes eye examinations and balance tests.

“Somebody like me with MS that has balance issues that has had speech issues in the past in flare ups, things like that, my speech sounds like I’ve had 30 beers,” Gray said. She also says her condition means she has short-term memory issues.

Nonetheless, Gray passed the evaluation.

“I passed that test, thank goodness, but I was just thinking ‘this is so not OK.’ I really should have been taken to emergency and have a doctor determine my impairment, not a drug recognition expert. He might be an expert in drugs, but he’s not an expert in medical conditions.” Halifax RCMP confirmed Gray was never charged with anything.

Although Gray was found to not be impaired, she lost her licence for a week and had to pay $150 to have it reinstated and reprinted. She also had to pay $250 to get her car back, and she missed four days of work because she doesn’t live on a bus route and couldn’t get to work without her vehicle. VICE has viewed Gray's driving suspension ticket, as well as her receipt for picking up her car.

RCMP Halifax spokeswoman Lisa Croteau told VICE the provincial penalties for failing a roadside test kick in, regardless of if a person is impaired under the criminal code.

“If they’re over it doesn’t matter if it’s for medical use or not, they shouldn’t be driving. If their prescription is at an amount that would make them fail the roadside, then they have to take the precautions not to be driving while they’re under the influence of it.”

Gray said if it happens again she could lose her licence for an even longer period of time and her insurance will be at risk of going up.

When the federal government passed bill C-46 last year, it introduced a host of new impaired driving laws.

Having between two and five nanograms of THC per millilitre of blood within two hours of driving would be punishable by $1,000 fine.

Having five or more nanograms of THC per millilitre of blood within two hours of driving could be considered a summary or indictable offence, punishable by a fine of $1,000 on the lower end to a maximum of 10 years in jail for repeat offenders.

Having booze and THC in your system (50 mg or more of alcohol per 100 ml of blood plus 2.5 ng or more of THC per ml of blood) would also be a hybrid offence (indictable or summary) and would again be punishable by a fine of $1,000 on the lower end to a maximum of 10 years in jail for repeat offenders.

In addition, provinces have implemented their own punishments relating to impounding vehicles and licences.

However, there is no definitive link between the amount of THC in a person’s system and impairment. THC is stored in a person’s fat cells and can remain detectable in a person’s body for up to a month. For medical patients or regular users, this means they may often not be legally allowed to drive.

Gray said her doctor told her “you could have gone a week without consuming it and you still would have hit positive.” Various experts and studies have claimed you should wait anywhere from two to 12 hours after consuming cannabis to drive.

The government-approved oral fluid tests have faced scrutiny over their accuracy. They are meant to operate in temperatures ranging from 4 to 40 degrees celsius. Gray said at the time she was arrested, it was below freezing. She had to get out of the car to do the test.

Cannabis lawyer Jack Lloyd told VICE Gray’s situation illustrates some of the major flaws with the new impaired driving laws.

“We have an individual arrested but not charged and her vehicle seized for a week. She was not impaired by alcohol statutorily but she was impaired by cannabis statutorily which is a real cause for concern for medical cannabis patients in Canada,” Lloyd said.

“She has used medical cannabis for many years so it is very unlikely she was actually impaired in any way.”

Gray said she believes the government should have put in much more thought into how it was going to regulate cannabis, and particularly impaired driving. She said her PTSD was also exacerbated by the experience.

“I had the night sweats. I felt like an infringement was happening on my... rights.”

Several lawyers, including Lloyd, have already indicated their plans to launch a constitutional challenge against aspects of Bill C-46.